communications nw paper review

8/17/2019 Communications Nw PAPER REVIEW

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Communication Network (Paper Review)

By Girma AbebeID.No:GSR/02935/07Communication n!ineerin! "G 2#t year


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"er(ormance

o(SD)A *it+

Sc+e,u-in!2


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Abstract

+e aer #tu,y t+e er(ormance o( inte--i!ent#c+e,u-in! (or #ace,i1i#ion mu-ti-eacce##SD)A 4ire-e## net4or#

SD)A i# a rinci-e o( ra,io re#ource #+arin! t+at

re-ie# on t+e ,i1i#ion o( t+e #ace ,imen#ion into#earate, communication c+anne-#.Ba#e, on t+e e6i#tin! #c+eme& a ne4 me,ium

acce## rotoco- )AC (or mu-time,ia SD)Aacet net4or# 4a# roo#e,

+e imro1e, rotoco- er(orm# #c+e,u-in! ba#e,on u#er# #atia- c+aracteri#tic# an, 8ua-ityo(#er1ice oS arameter# to ac+ie1e t+rou!+utmu-ti-ication an, acet ,e-ay re,uction.

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INRD;CIN

In t+e re#ence o( mu-time,ia tra


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Cont,

+e nee, (or coor,inate, )AC an,+y#ica- -ayer# in a #y#tem arc+itecture i#ronounce, in antenna array net4or#.

SD)A #c+eme attemt# to mu-ti-y t+e

t+rou!+ut o( a *@AN by incororatin!#atia- c+anne-#

>or a #y#tem 4it+ ) antenna e-ement#& t+eun,er-yin! i,ea i# to ,i1i,e eac+ time

,i1i#ion mu-ti-eacce## D)A #-ot into )space slots so that the total number ononinter(erin! #-ot# i# increa#e, by ) (o-,.

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Cont,

In SD)A& t+e er(ormance o( t+e#y#tem can be en+ance, 4it+ #atia-#i!nature ba#e, #c+e,u-in!

;n,er #tea,y tra


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Cont,

In mo#t rea- #cenario#& t+e net4or tra


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ANNNA ARRA "ACN*RS

Spatial Beamforming +rou!+ contro--in! antenna array beam pattern& anantenna array can improve #ome ey oerationarameter# #uc+ a# t+e !"NR o1er #in!-e antenna4ire-e## #y#tem

In t+e ab#ence o( noi#e& t+e re#on#e o( an )e-ementantenna array to a narro4ban, #ource can be 4ritten a#

yt Ey%t y2tF y)t a#t

4+ere . ,enote# tran#o#ition& an, a%a2Fa) i# t+e array re#on#e 1ector t+at cature# t+e #atia-

c+aracteri#tic# ,irectiono(arri1a-#& number o(mu-tiat+ reHection#& an, attenuation a##ociate, 4it+t+e termina-.spatial signature


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>i!. % ,eict# a tyica- antenna array#y#tem 4+ere t+e #atia- ,i1er#ity i#

e6-oite, (or mu-ti-e acce##communication#

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Cont,

*+en d termina-# communicate #imu-taneou#-y 4it+t+e ba#e#tation& t+e tota- outut o( t+e antenna array i#!i1en by

yt astJnt##tJnt

AEa%& a2&F a, tE#%t& #2tF #,t

nt En%t&n2t&F&n)t

◦ 4+ere nt i# an a,,iti1e noi#e 1ector an, # i# ,eKne, a# t+earray maniold whose columns are the spatial signatures.

A##ume

% a-- #i!na-# +a1e unit o4er an, LLaLL% i.e.&

er(ect o4er contro- an,

2 t+e noi#e i# i.i.,. 4it+ #tren!t+ . n2

3 ;n,er t+e#e a##umtion# t+e co1ariance matri6 o(t+e array outut +a# t+e (orm o(

%0


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Cont,

o retrie1e in,i1i,ua- #i!na-#& e.!.& #t& (rom t+eantenna outputs& outut# o( t+e antenna arrayare 4ei!+te, an, #umme, 4it+ a #et o( 4ei!+tcoe


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SDMA/TDMA Pacet!etwors +e #-otte, acet net4or con#i#t# o( $ ra,io

termina-# acti1e-y communicatin! 4it+ aba#e#tation.

In(ormation i# tran#mitte, in b-oc# o( #ymbo-#

ca--e, pacets. The time a"is is di#ided into timerames o $"ed length.%ach rame is e#enly di#ided into L time slots

through which multiple pacets can betransmitted.

%ach termina- tran#mit# acet# in one out o( % t+e #-ot# at a K6e, ,ata rate.

A##ume t+at t+e ba#e#tation +a# tota- contro- o(t+e net4or tra


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Cont,

*+en a termina- +a# acet# to tran#mit& it -ace#an a,mi##ionre8ue#t acet t+rou!+ a re#er1e,re8ue#t #-ot& (rom 4+ic+ t+e ba#e#tation obtain# t+e#atia- #i!nature an, tra


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Cont,>i!. 2 i--u#trate# +o4 t+i# obPecti1e i#

ac+ie1e, in a ?#-ot& %0termina-

SD)A/D)A net4or . +e SD)A e6an,# t+e caacity by a--o4in!

mu-ti-e u to ) termina-# in eac+ #-ot& an,4it+in eac+ #-ot #atia- beam(ormin! i#

er(orme, to ac8uire acet# (rom mu-ti-etermina-#

%?


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Cont,

In e##ence& SD)A a,,# anot+er ,imen#ion to t+e#ectrum re#ource by e6an,in! eac+ #-ot into )#ace #-ot# 1ertica- a6i#& tran#-atin! into an )(o-,increa#e o( #y#tem t+rou!+ut in an i,ea- #cenario

In rea-ity +o4e1er& t+e abi-ity o( caturin! mu-ti-eacet# ,een,# critica--y on t+e #atia-conK!uration o( t+e co#-ot termina-#.

Intuiti1e-y& by a##i!nin! Qmo#tort+o!ona-termina-# to t+e #ame time #-ot& t+e 4or#t ca#e an,a1era!e er(ormance o( t+e #y#tem can beimro1e,.

+e #c+e,u-in! a-!orit+m# #earate# Qa-i!ne,termina-# #o t+at t+e #atia- re#ource i# e


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Scheduling Algorithms

accommo,ate acet# 4it+ K6e, #ie into t+etime #-ot# to imro1e t+e #y#tem er(ormance.

A##ume t+at t+e tran#mi##ion ,ata rate o( eac+termina- i# K6e,. +en t+e termina- +a# to

oerate abo1e certain SINR t+re#+o-, SINRmin toa1oi, e6ce##i1e acet error#. +e t+re#+o-, ,een,# on t+e co,in! an,

mo,u-ation #c+eme an, t+e acet "Rre8uirement.

In t+e #c+e,u-in! roce##& a termina- i# a--ocate,to a time #-ot a# -on! a# t+e re#u-tin! SINR a(terbeam(ormin! i# abo1e t+e t+re#+o-, SINRmin

%'


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Be#tKt #c+e,u-in!a-!orit+mKr#t ic a termina- ran,om-y (rom t+e

termina- oo- to en#ure t+e (airne##amon! termina-#.

+e a-!orit+m te#t# t+e currentuna--ocate, termina- by ca-cu-atin! t+eSINR# (or a-- co#-ot termina-# in t+ecurrent time #-ot a# i( t+e can,i,ate

termina- 4ere to be a,,e,. +e SINR mar!in# o( co#-ot termina-#

are ca-cu-ate, by #ubtractin! SINRmin(rom t+e SINR

%7


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Cont,

A##ume t+ere are d termina-# in current #-ot& +eSINR mar!in o( t+e it+ termina- in t+i# #-ot i#:

SINRmar!in iSINR iSINRmini

+e SINR mar!in o( t+i# #-ot i# SINRmar!in

minSINRmar!ini +e a-!orit+m 4ou-, te#t a-- t+e time #-ot# an,

in#ert t+e termina- into t+e time #-ot 4it+ t+e-ar!e#t SINR mar!in ro1i,e t+at t+e mar!in i#!reater t+an ero. t+er4i#e& t+e termina- i#

i!nore,. +e a-!orit+m t+en ran,om-y ic# t+e ne6t

termina-. +e roce## continue# unti- a-- t+etermina-# are te#te,.

%


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Cont,

+e be#tKt #c+eme im-icit-y a##ume# t+at t+etra


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@et Mm5 5D%C be $ t+e mobi-e termina-#

in t+e #y#tem& an, m-(0% Mm-%&m-2&Fm-,i Nbe t+e termina- #et a--ocate, to t+e -t+ time #-ot in t+e (%t+ (rame. +en& in t+e( t+ (rame& t+e Qartia-Kt a-!orit+mu,ate# t+e termina- a--ocation a#(o--o4#:

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>i 3 t+ ( i ( SD)A b


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>i! 3& t+e er(ormance !ain o( SD)A bycomarin! t+e termina- (rame t+rou!+ut o(ure D)A #in!-e antenna& ran,om SD)Atermina-# a--ocate, to #-ot# 4it+out

re!ar,in! to t+eir #atia- #i!nature#& an,be#tKt SD)A/D)A.

2%


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Cont,C-ear-y& SD)A/D)A i# (un,amenta--y better

t+an ure D)A in t+at eac+ termina- +a#

(our time# t+e c+ance to tran#mit#ucce##(u--y.

To4e1er& t+e 4or#t ca#e er(ormance o(ran,om SD)A cou-, be e1en 4or#e t+an

ure D)A ,ue to +i!+ o##ibi-ity o(co--i#ion# o( coc+anne- termina-#.

*it+ #im-e )AC -ayer -annin!& t+e #y#temt+rou!+ut o( be#tKt SD)A/D)A increa#e#

#ub#tantia--y acro## t+e boar,.)ore imortant-y& t+e 1ariance o( t+e

termina-# t+rou!+ut become# 1ery #ma--&one can ractica--y u#e t+e a1era!e

t+rou!+ut a# t+e ,e#i!n arameter (or t+e# #tem ca acit . 22


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SCTD;@ING "RC@ >R);@I)DIA RA>>IC

In t+e re#ence o( mu-time,ia tra


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Cont,

#c+e,u-in! rotoco- t+at #i!niKcant-y increa#e#t+e er(ormance o( a mu-time,ia SD)A net4orby incororatin! t+e (o--o4in! oS arameter# SINR

"acet timeout

"acet -o## rate

con#i,er a #in!-ece-- net4or 4it+ one ba#e#tation an, N mobi-e termina-#. >i6e,-en!t+acet# arri1e at t+e mobi-e# accor,in! to

bur#ty ran,om roce##e#. +e acet# are bu=ere, at t+e mobi-e

termina-# unti- t+ey are tran#mitte, to t+eba#e#tation.

2?


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Cont,

*+en a mobi-e termina- +a# acet# totran#mit& it #en,# an acce## acet in t+eacce## #-ot u#in! A@TA ran,om acce##.

A(ter t+e ba#e#tation #ucce##(u--y recei1e#

an acce## acet (rom a mobi-e termina-& itobtain# in(ormation (rom t+e mobi-e termina-4+ic+ inc-u,e# t+e oS c-a## o( t+e acet#an, t+e #atia- #i!nature o( t+e termina-

Ba#e, on recei1e, in(ormation& t+eba#e#tation t+en !rant# certain time #-ot# tot+e termina- accor,in! to a ,e#ire, acettran#mi##ion o-icy.

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C t,


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Cont,

+e tran#mit ermi##ion i#

broa,ca#te, in t+e (o--o4in! ,o4n-in(rame.

+e mobi-e termina- -i#ten# to t+e,o4n-in (rame& 4+en it +ear# t+eermi##ion& it be!in# to tran#mit in t+ene6t u-in (rame.

ac+ time a mobi-e termina- tran#mit#

a acet& it a-#o inc-u,e# a"i!!ybacin! Re8ue#t to in,icate4+et+er it +a# more acet#bac-o!!e,.

+e ba#e#tation c+ec# t+e 2'


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Cont,

+e main obPecti1e o( t+e #c+e,u-er i# toma6imie t+rou!+ut an, minimieacet -o##. +i# i# ac+ie1e, in t4o #te#:

% ,etermine acet rioritie#U

2 a--ocate rioritie, acet# into SD)A/D)A #-ot#. +e#e ta## are er(orme, by a pacet prioriti&er and a pacet allocator,respecti#ely

t+e acet rioritier minimie# t+eacet -o##& 4+i-e t+e acet a--ocatorma6imie# t+e t+rou!+ut.

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Cont,

>i!. ?. "acet# a##i!nin!roce,ure

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Pacet Prioriti&er

A##ume t+at t+e t+ termina- +a# B bac-o!!e,acet# in it# bu=er& 4it+ timeout 1a-ue# Et%& t2&F

tB.

I,ea--y& i( e1ery acet in t+e 8ueue i# a--o4e, to

tran#mit at a minima- con#tant rate #o t+at itcan Kni#+ tran#mi##ion be(ore timeout& t+e rateo( t+e it+ acet i# .

+e a!!re!ate tran#mi##ion rate at current(rame i# t+u# .

It in,icate# +o4 many #-ot# are re8uire, by t+i#termina- at current (rame. *e can u#e t+ea!!re!ate tran#mi##ion rate a# t+emea#urement o( riority.

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Cont,

+e riority o( a acet i# ,eKne, a# t+ea!!re!ate tran#mi##ion rate o( t+i#acet an, t+e remainin! acet#bac-o!!e, a(ter it. So t+e riority o(

t+e it+ acet in t+ termina- 8ueue canbe ca-cu-ate, a#:

I( a acet cannot be tran#mitte, be(oreit# time out& it i# #im-y ,i#car,e,

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Cont,

"i i# a monotonic ,ecrea#in!(unction o( i.

It# 1a-ue reHect# +o4 ur!ent one

acet mu#t be tran#mitte,&becau#e a +i!+er 1a-ue in,icate# a+i!+er robabi-ity o( acet -o##.

+e 1a-ue a-#o in,icate# t+ea1era!e tran#mi##ion rate t+i#termina- #+ou-, +a1e.

3%


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Cont,

I( t+e 1a-ue i# !reater t+an one& it mean#more t+an one #-ot #+ou-, be a##i!ne, tot+i# termina- to a1oi, o##ib-e acet-o##.

A(ter rioritiation& t+e acet# are ut intoa >I> an or,ere, -i#t % accor,in! to t+eir

riority 1a-ue#. Notice t+at t+e (rame-en!t+ i# % . So one termina- can be

a##i!ne, u to % time #-ot#. So one termina-can +a1e at mo#t % riority 1a-ue#& an, itcan aear in t+e -i#t (or u to % time#

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Multimedia 'est()it Pacet Allocator A(ter rioritiation& eac+ or,ere, acet enter#

t+e bu=er 4it+ an a##ociate, SINR/,ata ratere8uirement an, a #atia- #i!nature.

+e obPecti1e o( t+e acet a--ocator i# to

arran!e acet# t+at +a1e t+e +i!+e#t riorityinto SD)A/D)A (rame# #o t+at t+e t+rou!+utin t+e ne6t (rame i# ma6imie,.

+e acet rioritier or,er# t+e acet#accor,in! to t+eir riority. +e acet a--ocator

t+en #earc+e# an, a--ocate# acet# accor,in!to t+eir riority or,er.

+e t+rou!+ut i# ma6imie, (or t+e !i1enacet riority or,er.

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CNC@;SIN

+e rotoco- % rioritie# t+e incomin! acet# ba#e,

on t+eir oS/timeout re8uirement# an,

2 Pu,iciou#-y #e-ect# coc+anne-termina-# ba#e, on t+eir #atia-#i!nature# to enab-e #i!niKcantimro1ement in t+e #y#tem t+rou!+ut,e-ay c+aracteri#tic#.

3?


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Re(erence

"er(ormance o( SaceDi1i#ion)u-ti-eAcce##SD)A *it+Sc+e,u-in!

By TuPun in, Member, *%%%,

and

Tui @iu& )ember& I

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'hankyou

communications nw paper review

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